MMSprotocol微软MMS协议详解.docx

MMS streaming protocol Website http://get.to/sdp

“putting the MMS jigsaw puzzle together piece by piece”

UPDATE HISTORY

Update 31.10.02
New MMS command 20 to client – command added.
Command 01 to client updated.
Command 05 to client updated.
Command 07 to server updated.
Command 11 to client updated.
Command 15 to server updated.

Update 01.10.02
Command 01 to Client – structure updated
Command 02 to Server – data updated
Command 02 to Client – data updated
Command 05 to Client – structure updated
Command 06 to Client – data added at end
Command 07 to Server – structure updated
Command 09 to Server – data updated
Command 0d to Server – data updated
Command 11 to Server – data updated
Command 1A to Server – data updated
Section ‘MMS Pre Headers’ the whole section was updated, new data added
Section ‘MMS Command Protocol State Sequences’ end details updated

Update 30.09.02
New section added : ‘IEEE 754-1985 double precision values’
All MMS functions in this document using this 8 byte double precision value have been updated, including the MMS command header section.
Command 05 to Client updated
Command 06 to Client updated
Command 07 to Server updated

Update 12.09.02
New section added : ‘MMS flags’ to hopefully explain further how they work.
Command 01 to server – text changed.
Command 02 to server and 02 to client – text changed.
Command 05 to client - basic structure now included.
Command 06 to client – structure extended
Command 11 to client – extra info added, now includes ‘packet pair’
Command 18 to server - updated
Section ‘MMS command protocol state sequences’ has been updated
Section ‘MMS pre-headers’ New item ‘MMS timing packet pairs’ added
Section ‘ASF UDP/TCP packet re-syncronisation’ updated.
Section ‘Time codes, media packets and ASF headers for live broadcasts’ extended with new summary.

Update 20.06.02
Document error correction in section:
‘MMS Pre Headers’ sub section : ‘MMS Header Pre-Headers’
The line did read “not including the pre header field”
And has been corrected and now reads “including the pre header field length”.

Update 04.05.02
New section added ‘MMS Proxy Servers’ - an overall explanation.
Section ‘Known MMS commands’ – Client to Server command 01 updated
Section ‘Known MMS commands’ – A new command added; server to client 0A.

Update 24 04.02
All references to ‘Session ID’ have been replaced with a new value ‘PacketIDType’

Update 23.04.02
Section ‘known MMS commands’ new data added to command 06 to client
Change made to command 07 to server (packet ID type)
Change made to command 15 to server (packet ID type)
Section ‘About error codes…’ some inaccurate text has been removed

Update 22.04.02
Section ‘known MMS commands’ new data added to command 01 to client
Section ‘MMS pre headers’ A re-write to explain more clearly how they work
Section ‘MMS state sequences’ has been cleaned up
All sections – Font updated to show hex codes more clearly

Update 20.04.02
Section ‘ASF UDP/TCP packet resynchronisation’ the UDP ‘beef food’ command updated
Section ‘known MMS commands’ regarding command 1A to server, updated
Section ‘known MMS commands’ regarding command 15 to client, updated

Update 20.03.02
Section ‘MMS command protocol state sequences’ - text added
Section ‘command 05 to server’ – updated with new DRM info

Update 13.03.02
Section ‘command 06 to client’ - updated with new info
Section ‘command 15 to client’ - updated with new info regarding data blocks
Section ‘command 18 to server’ – updated explanation

Update 01.03.02
Major news and update to document :- MicroSoft has released its own ASF v1.0 specification document and is now freely available at their website. And its about time too!. Because of this newly available information, this MMS document will now only contain information regarding MMS protocol and does not include ASF1.0 structures. Its been a long time coming, this information is a breakthrough in terms of writing new code using ASF 1.0. ie. Code using windows media format.

Section: ‘Lets talk about ASF format’ has been updated and all sections regarding ASF 1.0 removed.
Section: ‘Your personal data security flaw’ has been updated.

Update 18.01.02
Section ‘Error codes and Command level prefix 1” updated with a new CommandLevel value.
Prefix 1 data in some client to server commands has been updated with the CommandLevel value.
Section ‘Known MMS Commands’:
More data added to the 0x15 client to server command.
Slight change made to command 02 client to server extra data field.
Slight change made to command 05 client to server extra data field.

Section ‘The MMS command packet header’ has new appended text.

Update 15.01.02
New Acknowledgments section added at the end.
Section ‘known MMS commands’
Command 1A password encryption explained.
Command 01 to client – more information added

Section ‘Known GUIDs’ a new object has been added.

Update 30.12.01
Section - ‘Known MMS commands’
Command 1A both server and client sent, updated.
Command 01 to server and 01 to client updated
Command 18 to server and 15 to client updated
Command 06 to client updated
Section – ‘MMS Command Protocol State Sequences’ updated.

Update 28.12.01
Section – ‘known MMS commands’ :-
01 to client changed,
05 to server changed,
15 to client re-write and new data,
18 to server changed.

Update 12.12.01
Section – ‘known MMS commands’ has a new command ‘0x1A’ added to the list

Update 07.12.01
Section - ‘known MMS commands’ has new information on command 15 (to client) added
Section - ‘MMS command state sequences’ has been updated with new information
New section - ‘ Error Codes’ has been added

Update 29.11.01
Item – ‘Some known GUIDs for objects’ has been updated with a new URL object
Item – ‘ASF Header Objects’ has been updated with new data
Item – ‘Known MMS Commands’ new data added to command 01 to server

update 27.11.01
The document has been significantly re-written and now combines command specific data with MMS commands. The result is a more clear description of what is known of MMS commands and their inner data workings. There are distinct patterns now starting to emerge within commands. The addition of ‘prefix’ data should help developers to write command functions. This should be the way forward in the way this document is presented in the future.
Item – ‘The command 06’ has been updated with new information
Item – ‘Command Packets’ are now referred to as ‘Command Packet headers’

update 18.11.01
Item - ‘Stream Bit Rate Selection Object’ is now Stream MBR object - updated
Item under the ASF Header objects section – ‘File Object’ data has been updated
Other small text changes were made in the document, manly to clear up a few points

update 4.11.01
Section – ‘Known MMS Commands’ the commands 0x0d, 0x28 and 0x30 mentioned.
Section – ‘MMS pre Headers’ now includes new data
Section – ‘MMS command protocol State Sequences’ updated
Section – ‘Command Specific Data…’ updated, a re-write for command 0x07

update 1.11.01
Section – ‘ASF UDP/TCP packet resynchronisation’ has been totally re-written with new data
Section – ‘Known MMS commands’, 18 and 15 updated a little
Section – ‘Command specific data’ command 07 updated
Other small changes made

update 28.10.01
Section ‘ASF Header Objects’, a new streaming bit rate object has been added, also more updates to the existing objects.
Section ‘ Some Known GUIDs…’ has been updated with this new object

update 27.10.01
Section – ‘ASF Header Objects’, yet more data added regarding titles, versions and codecs

update 25.10.01
Section - ‘ASF Header Objects’ the Title, Version and Codec objects have been updated
Section - ‘Command specific data…’ sub-heading ‘Switch Elements or stream IDs’ has been updated

update 24.10.01
Section – ‘Some known GUIDs…’ has been updated with new GUID objects
Section – ‘ASF header objects’ has been updated with some new object data
New item – ‘Your personal data security flaw’

update 10.10.01
The command server to client 06 - new data has been entered.
Section: ‘You can download broadband media files with a narrow band modem!’ has been re-written
Section: ‘ASF Packet synchronisation…’ has been updated and extended
Section ‘ Switch’ Elements or Stream ID values in command packet’ has been updated
Section ‘ MMS Pre-Headers ‘ – has new data added
Section ‘MMS Command protocol state sequences’ – a small adjustment made in text

update 28.09.01
Section: ‘ASF Header object data ‘ - File Object table has been updated with new data.
Section: ‘Time Codes, media packets and ASF headers for Live broadcasts’ under summary has changed.
Section: ‘Notes regarding packet lengths and data rates’ has been updated.
A section showing IP packet, ASF packet and segment relationship has been added.

>>> Start of history

Intro with back to basics
There are two types of commonly used server, both can handle video and audio media transmission over the internet, but with good and bad points for each.
They are, Standard Host Web Servers and Streaming Media Servers.
Standard host servers use a basic HTTP protocol and are normally used for holding things like web sites, FTP and email. Streaming media servers are dedicated media servers and use two possible types of streaming application protocol (as used by MicroSoft ®). Those are HTTP version 1.0 or 1.1 and MMS (Multi Media Server) protocol. Note that the HTTP protocol used by streaming servers is a modified version of standard web server HTTP protocol and has extended pragma commands to allow real time streaming. Normal HTTP does not allow for this.
Streaming media servers have distinct differences compared to normal host web servers. One difference is that media placed on a normal host web server using standard HTTP protocol does not require a special server or software for viewing or even downloading. Another difference is that streaming servers using MMS (like Microsoft Windows Media Services) feed the media to the viewer in real time from a streaming server. This type of server using MMS can reach huge audiences while standard HTTP servers would slow down and eventually stop when large audiences log on at the same time.

Other server differences
In most cases, standard Host Web Server material can easily be downloaded by the viewer, simply by right hand clicking a link button on a web site. The viewer can then select ‘download’ and make a copy of the file on the local hard disk. This means the viewer can watch the file off line and at any time. Also, copies can be made of the media file. This kind of media transfer is called ‘progressive’ streaming and is similar to downloading a document or FTP file over the internet.
Streaming media servers on the other hand, are not so easily downloadable, in fact, they are not supposed to be downloadable at all! Microsoft has tried to ensure that no one has the information or software to do this. They have never supplied downloading software or protocol information simply because they do not want clients to be able to download material for copyright, pay per view model and traffic advertising reasons. Microsoft tell us that the content cannot be downloaded, reassuring that its safe and copy proof. Well, since this protocol is not even encrypted and most server operators don’t encode with digital rights management information (automatic artist web page referral), I find that assurance a little misleading.
Furthermore, every time a client wants to view a media, they must do so on line, with no copy or download ability being available. Fact: most on line streamed media breaks down while viewing. Something like 7 out of 10 streams will have to re-buffer at some point or worse, disconnect. And because you can’t download it for break free viewing later, then this is as good as it gets.
However, an application known as ASF Recorder.exe written by an anonymous writer some time ago allowed clients to download streamed HTTP v1.1 protocol media from a streaming media server. True MMS protocol streaming was still not available.

So what is MMS
MMS or Multi Media Server protocol is MicroSoft’s ® propriety streaming protocol. Its prime use is to carry over the internet, multi media broadcasts, archived videos, sound tracks, live shows and a whole load of other real time or pre-recorded programming material. A viewer, using this protocol, can watch a media file fed from a dedicated streaming server in the form of a TV picture or audio track on their computer. Microsoft has developed and supplied free media viewer software (currently Media Player 7.0 or 7.1 update) for anyone with a home computer and internet link. MMS is specifically designed to convey the media to the viewer as glitch free as possible over a network or internet medium. MMS is not to be confused with file formats like ASF, AVI or MOV, they are actual encoding formats where MMS is the ‘carrier’ of formats that makes up so called streaming technology. MMS operates on top of UDP or TCP transport protocols, they are transport/network level, where as MMS exists and operates at application level.

More about streaming protocols.
There are two types of media streaming protocol used by Microsoft® at this time for streaming over the internet. These are outlined below.

HTTP 1.0 / 1.1 streaming protocol
This protocol uses a streaming protocol based on standard host server HTTP but differs in that it has some special extended pragma commands to allow real time streaming. This has already been explored with success by the anonymous writer of ASF Recorder. Sites using HTTP streaming protocol can be connected to and downloaded from using this available software. Sites that use this protocol may have the prefix HTTP:// or sometimes MMS:// with its HTTP streaming enabled, depending on the settings set by the server provider. This document will go no further in discussing this type of protocol since the work by the anonymous writer has already given an excellent protocol description and a fine piece of C coding. We salute you!
This type of streaming protocol seems to be used less these days by professional servers with more and more server owners switching to the MMS streaming protocol. Probably for security and lower overhead reasons.

MMS Streaming protocol
This protocol is used extensively today by Microsoft’s streaming servers which operate on Windows NT server or Windows 2000 server platforms. Streaming server applications like Windows Media Services and NetShow using this protocol can stream in real time to many viewers simultaneously using different possible transport protocols like TCP and UDP. Servers using MMS streaming have the URL prefix MMS:// or MMST:// for T